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Velvetbean ( Mucuna sp., n=11), a self-pollinated species, is an important legume used in tropical agricultural systems in rotation with other crops for nematode management and/or soil improvement. A genetic map of velvetbean was constructed in order to identify potential molecular markers linked to important morphological and agronomic traits that would be particularly useful for developing and improving the species. Traits such as seed coat color, pod color, and pod pubescence were among the main parameters observed in a process of genetic diversity estimation. Two slightly divergent velvetbean accessions, PI364362 and 'Edgar Farm White', a land race from Alabama, were used to make an intraspecific F(1) hybrid. Amplified fragment length polymorphism analysis (AFLP) detected an average of six polymorphic fragments per primer pair between the two parents. As expected for dominant markers, the sum of all AFLP bands from both parents was generally observed to be present in the AFLP profiles of the F(1) progeny, indicating full penetrance and the dominant nature of AFLP markers. An F(2) population was generated by self-pollinating a single F(1) plant. Using 37 AFLP primer pairs, we detected 233 polymorphic markers of which 164 (70.4%) segregated in 3:1 Mendelian ratios, while the remaining 69 (29.6%) both segregated and were scorable. The genetic linkage map constructed from this population comprised 166 markers, including two morphological traits (pod color and pod pubescence). Twenty linkage groups were found with an average distance between markers of 34.4 cM, covering a total of 687.9 cM. The linkage groups contained from 2 to 12 loci each and the distance between two consecutive loci ranged from 0 to 21.8 cM. The newly designated morphological traits pod color ( pdc) and pod pubescence ( pdp) co-segregated with each other at a distance of 4.2 cM. Two DNA markers designated ACGCAG2 and ACTCTG1 were located in the same group as pdc and pdp. The AFLP linkage map provides opportunities for use in marker-assisted selection and in the detection of loci controlling morphologically important traits.

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Foot and mouth disease (FMD) is endemic in African buffalo (Syncerus caffer) in the Kruger National Park (KNP) and surrounding game parks in South Africa. The last outbreak of the disease in domestic stock outside the FMD control zone occurred in 1957. Due to the success in containing the disease, the country was accorded zone freedom from FMD without vaccination by the Office International des Epizooties (OIE: World organisation for animal health) in 1995. This status was lost in September 2000 when the first-ever recorded case of serotype O in South Africa was diagnosed in a piggery in KwaZulu-Natal after the illegal feeding of untreated swill. In November 2000, an outbreak of FMD caused by serotype South African Territories (SAT) 1 was diagnosed in a feedlot within the free zone of Mpumalanga Province. The SAT 1 outbreak was traced to cattle in the FMD control zone south of the KNP after the game-proof fence surrounding the KNP was severely damaged by floods. This enabled buffalo to come into direct contact with cattle outside the KNP. A further outbreak caused by SAT 2 was diagnosed within the FMD control zone in February 2001, also as a result of buffalo having escaped from the KNP. All these outbreaks were successfully contained, with the re-instatement of zone freedom from FMD without vaccination by the OIE in May 2002. These outbreaks made it necessary to re-examine the methods of control and containment of FMD that have been practised for many years and which are in line with accepted international practices. The authors describe the rationale for the different control strategies that were followed, the need for a multidisciplinary approach to disease control, the interface between control and technological and diagnostic support and the lessons learned. Some suggestions for future control strategies are also offered.

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Isoflavones and carotenoids in four experimental genotypes and Hutcheson cultivar soybeans were evaluated as a function of processing treatments and maturity. Total isoflavone and carotenoid contents were affected by genotypes and maturity stages (p < 0.0001). Total isoflavones ranged from 472 microg/g (in NTCPR93-40) to 2280 microg/g (in Hutcheson). Lutein contents ranged from 895 (in NTCPR93-286) to 2119 (in Honey Brown), and beta-carotene ranged from 291 (in Hutcheson) to 491 (in NICPR92-40) microg/100 g. Mean total isoflavone retention percentages in immature Hutcheson soybeans were 46% (boiling), 53% (freezing), and 40% (freeze-drying). Mean retentions of lutein and beta-carotene, respectively, were 92 and 73% in frozen, 62 and 62% in boiled, and 34 and 27% in freeze-dried soybeans. Boiling caused a substantial increase in daidzin, genistin, and genistein. The results show that post-harvest changes in total isoflavones and carotenoids in soybeans are influenced by processing methods, but genotype has an effect on isoflavone and carotenoid profiles during seed development.

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Soybean (Glycine max) yield often is limited by the phytoparasitic nematodes Meloidogyne spp. and Heterodera glycines in the southeastern United States. We studied the effects of rotation with bahiagrass (Paspalum notatum), velvetbean (Mucuna pruiens), or continuous soybean, aldicarb, and soybean cultivar on yield and population densities in two fields infested with a mixture of Meloidogyne spp. and H. glycines. Velvetbean and bahiagrass reduced population levels of both nematode species to near zero prior to planting soybean. At harvest, both nematode populations were equal in soybean following bahiagrass and continuous soybean but were lower following velvetbean. Both bahiagrass and velvetbean as previous crops were equal in producing significantly (P < 0.003) higher yield than continuous soybean. Velvetbean increased subsequent soybean yield by 98% and bahiagrass increased subsequent soybean yield by 85% as previous crops compared to continuous soybean. The major differences between the two rotation crops were yield response of the nematode-susceptible cultivars and at-harvest nematode populations. Velvetbean tended to mask genetic differences among cultivars more so than bahiagrass. Velvetbean also produced a more long-term effect on nematode populations, with numbers of both Meloidogyne spp. and H. glycines lower in soybean following velvethean than following bahiagrass or continuous soybean.

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Frogeye leaf spot (FLS) caused by Cercospora sojina Hara is a disease of soybean (Glycine max (L.) Merr.) that causes significant seed yield losses in warm, humid environments of southeastern United States. The Rcs3 gene in soybean has been reported to condition resistance to all known races of C. sojina. The objectives of this study were to determine the effectiveness of Rcs3 in limiting seed yield loss due to FLS and to compare the seed yield of the resistant and susceptible near-isolines (NILs) in the absence of significant FLS disease. Four pairs of NILs-Colquitt/Colquitt-Rcs3, Gordon/Gordon-Rcs3, Thomas/Thomas-Rcs3, and Wright/Wright-Rcs 3-were evaluated in 23 field experiments in Alabama, Florida, Georgia, Louisiana, Mississippi, and South Carolina during 1992 to 1994. The amount of damage to susceptible soybean caused by FLS was dependent on the specific environment. All four of the Rcs3 NILs were resistant to the prevalent races of FLS in all environments. In the absence of significant FLS disease, each of the Rcs3 NILs was at least equal to the respective susceptible line in its seed yield. In the presence of FLS infestation, the susceptible lines suffered significant seed yield loss (up to 31%) compared to their Rcs3 NILs. The effect of FLS on seed yield was dependent on cumulative disease severity over the growing season. Thus, the area under disease progress curve was more useful than percent of leaf area infected at the end of the growing season (R7 stage of development) in explaining the seed yield loss due to FLS.

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Host physiological events in relation to infestation by parasitic nematodes are not well documented. Soybean plant responses to Meloidogyne incognita infestation were compared to resistant (Bryan) and susceptible (Brim) cultivars at 0, 1, 3, 10, 20, and 34 days after infestation (DAI). The resistant cultivar had higher chitinase activity than the susceptible cultivar at every sample time beginning at 3 DAI. Results from isoelectric focusing gel electrophoresis analyses indicated that three acidic chitinase isozymes with isoelectric points (pIs) of 4.8, 4.4, and 4.2 accumulated to a greater extent in the resistant compared to the susceptible cultivar following challenge. SDS-PAGE analysis of root proteins revealed that two proteins with molecular weights of approximately 31 and 46 kD accumulated more rapidly and to a higher level in the resistant than in the susceptible cultivar. Additionally, three major protein bands (33, 22, and 20 kD) with chitinase activity were detected with a modified SDS-PAGE analysis in which glycolchitin was added into the gel matrix. These results indicate that higher chitinase activity and early induction of specific chitinase isozymes may be associated with resistance to root-knot nematode in soybean.

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The effects of cropping systems (fallow, rotation with sorghum-sudangrass hybrid [Sorghum bicolor x S. sudanense], and continuous soybean [Glycine max]), nematicide (aldicarb) treatment, and soybean cultivar on yield and nematode population densities were studied in a field infested with a mixture of Meloidogyne spp. and Heterodera glycines. Soybean following sorghum-sudangrass yielded 111 kg/ha more than soybean following fallow and 600 kg/ha more than continuous soybean. Aldicarb treatment increased yield by 428 kg/ha, regardless of previous crop. Cultivars interacted significantly with nematicide treatment and previous crop with respect to yield. Sorghum-sudangrass reduced numbers of Meloidogyne spp. compared with fallow and continuous soybean, but cropping system did not affect H. glycines numbers. The cultivar x previous crop and cultivar x nematicide interactions were significant for numbers of Meloidogyne spp. and H. glycines. We concluded that sorghum-sudangrass hybrid and fallow are effective in reducing yield losses caused by mixed populations of Meloidogyne and H. glycines. Highest yields were obtained using crop rotation and cultivars with the highest levels of resistance to both nematodes.

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The effect of previous crops - soybean (Glycine max) or velvetbean (Mucuna deeringiana) - and aldicarb on yield and nematode numbers for selected soybean cultivars was studied in a field infested with a mixture of Meloidogyne arenaria and Heterodera glycines. Soybean following velvetbean yielded 959 kg/ha more than soybean following soybean. Nematicide treatment resulted in increased yield, and there was no interaction between nematicide treatment and previous crop. Cultivars interacted significantly with nematicide treatment but not with previous crop for yield. Velvetbean reduced numbers of H. glycines but not M. arenaria. Cultivars interacted with previous crop, and the previous crop x nematicide x cultivar interaction was significant for both M. arenaria and H. glycines. We concluded that velvetbean is effective in reducing yield losses caused by mixed populations of M. arenaria and H. glycines, regardless of genetic resistance of soybean cultivar.

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The relative efficacy of rotations of soybean with sorghum and tropical corn for nematode management was studied for 2 years in a field infested with root-knot (Meloidogyne arenaria) and soybean cyst (Heterodera glycines, race 14) nematodes. Corn, sorghum, and soybean cv. Kirby were planted in 1989, and in 1990 the same areas were planted with seven soybean cultivars with and without at-plant application ofaldicarb. Corn and sorghum did not support H. glycines, but significant juvenile populations of the nematode in soil were associated with Kirby soybean. Numbers of H. glycines and M. arenaria juveniles in 1990 depended on cultivar and cropping system but were little affected by nematicide treatment. Lowest numbers of H. glycines juveniles were associated with Leflore soybean and the corn-soybean rotation. Numbers of M. arenaria juveniles were highest with Leflore and lowest with Braxton and Brim soybean. The sorghum-soybean rotation resulted in slightly higher numbers of M. arenaria juvenile populations than soybean monoculture or the corn-soybean rotation. Aldicarb increased yields of some cultivars, but its use was not justified economically. Yields of all cultivars were from 19-287% higher in rotation systems than in monoculture.

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Previous cropping sequence (corn-soybean vs. soybean-soybean) and aldicarb effects on soybean yield and nematode numbers at harvest for soybean cultivars with various combinations of nematode resistance were determined in 1988 in a sandy loam soil infested with Meloidogyne arenaria race 2 and Heterodera glycines races 3 and 4 at Elberta, Alabama. Yield and nematode numbers differed among cultivars with 'Leflore' having the highest yield. Aldicarb treatment resulted in increased soybean yield but did not affect nematode numbers. Previous cropping sequence did not affect soybean yield or numbers of H. glycines, but soybean following corn-soybean had higher numbers of M. arenaria than soybean following soybean-soybean. The only significant statistical interaction was aldicarb x cultivar for numbers of H. glycines.

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The effect of previous crops--soybean (Glycine max) or corn (Zea mays)--and aldicarb (2.2 kg a.i./ha) on yield and nematode numbers at harvest for soybean cultivars with various combinations of nematode resistance was determined in a sandy loam soil infested with Meloidogyne arenaria race 2 and Heterodera glycines races 3 and 4 at Elberta, Alabama, in 1987. Cultivars had an effect on yield and nematode numbers (P = 0.01), as did the interaction of previous crop and cultivar. The nematicide treatment x cultivar interaction was significant for yield, and the three-way interaction was significant for numbers of M. arenaria. A previous crop of corn had no effect on M. arenaria numbers, but it reduced numbers of H. glycines from 93 to 25 J2/100 cm(3) of soil and increased soybean yield from 1,963 to 2,560 kg/ha. Aldicarb reduced M. arenaria numbers from 230 to 186 J2/100 cm(3) soil and increased yield from 2,062 to 2,460 kg/ha but it had no effect on H. glycines numbers. Rotation with corn was an effective control measure for H. glycines and enhanced the yields of H. glycines-susceptible cultivars.

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A field study was conducted to evaluate one susceptible and six nematode-resistant soybean cultivars for their effects on seed yield, nematode populations, and response to a fumigant nematicide, ethylene dibromide. The soil was a sandy loam, and the field was infested with a mixture of Meloidogyne incognita, M. arenaria, and Heterodera glycines. Soybean cultivars significantly affected yield and juvenile numbers of Meloidogyne spp. but did not affect the H. glycinesjuvenile population. Fumigation increased yield and numbers of H. glycines juveniles, whereas the numbers of Meloidogyne spp. juveniles were decreased. The interaction between cultivars and fumigation treatment was significant for yield but not for nematode numbers.

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One susceptible and six nematode-resistant soybean cultivars were evaluated in the field for their effects on seed yield, nematode populations, and response to the fumigant nematicide, ethylene dibromide. The soil was a loamy sand infested with Meloidogyne arenaria and Heterodera glycines. Cultivars significantly affected yield and numbers of H. glycines but did not affect M. arenaria numbers. Fumigation increased yield and reduced M. arenaria numbers but did not affect numbers of H. glycines. The interaction between cultivars and fumigation was significant for yield but not for nematode numbers.

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Three bovine carcases displaying inter- and intramuscular, intra-abdominal and intra-thoracic lesions attributable to Parafilaria bovicola infestations were selected for further inspection at Cato Ridge abattoir. The distribution of these lesions in the carcase is described. The condition was confirmed by the presence of eosinophils in scrapings and histological sections of the lesions and by the recovery of the parasite.

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Records indicate that Parafilaria bovicola-infested cattle slaughtered at the Cato Ridge abattoir originate from certain areas not previously recorded. Furthermore, moderate to severe infestations are diagnosed significantly more frequently in the entire male bovine than in female animals or oxen (castrated males). The data under review cover the period March 1981-August 1982, a period of 18 months.

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Evidence presented shows a 585% increase in the compounded total carcase condemnations for parafilariasis at the Cato Ridge abattoir in the year July 1981/June 1982 as compared with July 1979/June 1980. There is also evidence which points to condemnations occurring in bi-annual cycles with peaks in November/December and June.

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